1. Field of the Invention
This invention relates to a magnetic head for impressing a magnetic field across a magnetic tape by being contacted with a running magnetic tape, a tape cartridge used for data backup for a personal computer, an office computer or the like, and a recording/reproducing apparatus carrying the magnetic head and having the tape cartridge loaded thereon.
2. Description of the Related Art
The recording/reproducing apparatus is connected to a personal computer, an office computer or the like and used with a data cartridge loaded thereon. With the data cartridge, data signals accumulated in, for example, a memory of a main portion of a computer are sucked and recorded by a magnetic head on a recording medium, such as a magnetic tape, magnetic disc or a magneto-optical disc. Alternatively, data signals recorded on the recording medium are reproduced by a magnetic head and supplied to, for example, a memory of the main portion of the computer.
In a data cartridge having a magnetic tape as a recording medium, for example, a main body portion of the cartridge is formed by combining a cover substantially in the shape of a shallow saucer and a base paste 201 substantially in the shape of rectangular plate to form a main body portion of the cartridge. Within the interior of the cartridge main body portion are mounted a pair of reel pins 202, tape guide pins 203 and guide roll pins 204. On the reel pins 202 are rotatably mounted a tape supply reel and a tape take-up reel carrying a coil of a magnetic tape 205. A magnetic tape 205 is placed around the reel pins 202. The guide roll pins 204 carry a driving mechanism having an endless belt adapted for rotationally driving the tape supply reel and the tape take-up reel.
A magnetic head 206, provided on the recording/reproducing apparatus, has a pair of magnetic core halves 207, 208 abutted and connected to each other with a back gap g2 as a boundary, as shown in FIG. 2. The magnetic core halves 207, 208 are provided with track width control grooves 209, 210 for adjusting the track width of the front gap g1. Within each of the track width control grooves 209, 210 is charged the fused glass 211 for bonding the core halves together.
The magnetic head 206 has a coil-winding slot 212 towards abutment surfaces 207a, 207a of the magnetic core halves 207, 208 in order to permit winding of a coil, not shown. The magnetic head 206 has winding guide slots 213, 214 for assisting the coil winding on opposite lateral surfaces 207c, 208c of the winding slot 212 of the magnetic core halves 207, 208.
When the above-described data cartridge is loaded on the recording/reproducing apparatus, a magnetic head 206 provided on the side of the recording/reproducing apparatus is thrust a pre-set amount for recording or reading data signals with respect to the magnetic tape 205, as shown in FIG. 3. At this time, as the magnetic tape 205 is thrust by the magnetic head 206 provided on the side of the recording/reproducing apparatus, the magnetic tape 205 in the data cartridge is subjected to tape tension which is a resistive force the magnetic tape 205 exerts against the magnetic head 206. As the take-up ratio by the tape take-up reel is increased, the magnetic tape 205 is subjected to tape tension which is increased gradually with increase in the take-up ratio by the tape take-up reel, as shown in FIG. 4.
If the magnetic tape 205 is subjected to increased tape tension and vibrations in the tensioning direction are small, the magnetic tape 205 has good contact with the magnetic head 206 of the recording/reproducing apparatus, thus assuring stable recording/reproduction.
However, if the magnetic tape 205 is subjected to vibrations in the running direction as indicated by arrow X in FIG. 5, the playback position of the magnetic head 206 with respect to the magnetic tape 205 is instantaneously moved such that the magnetic head cannot recognize data signals to produce data errors.
Moreover, if the magnetic tape 205 is subjected to off-track as a result of transverse vibrations as indicated by arrow Y in FIG. 5, there is produced deviation in the reproducing position or recording position of the magnetic head 206 when reproducing or recording a track recorded on the magnetic tape 205 by the magnetic head 206 thus giving effect to data errors.
In addition, in a data cartridge, since the tape tension is changed with the tape take-up ratio, the contact pressure between the magnetic tape 205 and the magnetic head 206 on the side of the recording/reproducing apparatus is changed when the tape tension is decreased or the vibrations in the tensioning direction as indicated by arrow Z in FIG. 5 are increased, thus varying the contact pressure between the magnetic tape 205 and the magnetic head 206 on the recording/reproducing apparatus, thus again giving rise to data errors.
In order to provide a data cartridge freed of these causes of data errors, it may be contemplated to control the vibrations in the direction of tension and width and in the tape running direction of the magnetic tape 205 at a position between the root portion and an anti-extraction flange provided around the rim of the upper edge of the tape guide pin 203 while the magnetic tape 205 runs between the two tape guide pins 203.
However, with this data cartridge, the distance from the root of the tape guide pin 203 to the flange needs to be kept equal to the width of the magnetic tape 205, such that the edge of the magnetic tape 205 is worn out due to contact with the major surface portion of the base plate 201 or the flange, thus destructing the magnetic tape 205.
The fact that the running magnetic tape 204 undergoes vibrations is a serious problem in the case of a data cartridge in which the future tendency is towards a smaller track width of the magnetic tape 205, higher recording density and a thinner thickness.